Lithium hydroxide monohydrate produces a small amount of dust which is always present when being handled or poured. This dust is extremely choking and irritating to humans even in trace amounts. Large amounts of lithium hydroxide monohydrate are used in industrial grease manufacturing and the choking dust has been a major problem in its use.
Lithium hydroxide has also been used in closed-cycle oxygen systems such as the atmosphere which is found in closed places as submarines or in rebreathing appliances which are used in anesthesia or emergency oxygen equipment because it will react with carbon dioxide. In a rebreather system it is necessary that the carbon dioxide be 4% or less than the entire atmosphere inasmuch as a greater amount of carbon dioxide will result in a deleterious effect upon the person in the breathing apparatus. The use of lithium hydroxide has been complicated by the fact that anhydrous lithium hydroxide pellets tend to crumble and create the noxious dust.
U.S. Pat. No. 3,607,040 to Hervert et al has solved the problem of preventing the crumbling and dust formation of pellets by treating anhydrous lithium hydroxide with polyvinyl alcohol and then calcining the resultant mixture to remove any water. The problem with the use of polyvinyl alcohol is that a unitary treatment of lithium hydroxide is not possible for both powder and pellets since polyvinyl alcohol is not used in the production of grease.
U.S. Pat. No. 2,629,652 to Schecter et al discloses forming porous anhydrous, non-dusting granules of lithium hydroxide for use in closed space ventilation systems by pressing lithium hydroxide having a water content of between 40 and 45% under pressure of 18,000 to about 25,000 psi to form a cake, breaking the cake into granules and then heating the granules to a moderate elevated temperature. The dust problem is solved because the fine particles which cause dust are physically separated from the granules.
U.S. Pat. No. 2,846,308 to Baxendale disclosed the treatment of alkali hydroxides, which includes lithium hydroxide, with an ester or an organic acid or an ester or an inorganic acid in liquid form to reduce the hydroscopic properties of the alkali hydroxide for use as photographic developers. About 1 to 15% by weight of a lower alkyl acid ester which is liquid and can generate a volatile alcohol is utilized.
U.S. Pat. No. 5,106,608 to Retsching et al prepares high density ceramics with the use of magnesium oxide in fine powder form which is coated with surface-active materials that are hydrophobic. The coatings include metal soaps, siloxanes, silicones and organic polymers.
It is an object of the invention to provide a method for reducing the dust when handling lithium hydroxide monohydrate powders and granules.
It is another object of the invention to provide a pourable dust-free lithium hydroxide monohydrate powder.
It is yet another object of the invention to provide a pourable lithium hydroxide monohydrate powder which can be directly utilized to produce an industrial grease.